Emel Dilek, the much-younger mistress of a late luxury-car dealer, yesterday lost her court battle to keep the lucrative employment contract that he had secretly given her before his death.

During closing arguments in Manhattan federal court, Dilek’s lawyer told the judge that the unpaid remainder of her sweet $120,000-a-year deal was worth more than $385,000 — when you considered it included benefits such as the “M-class” luxury SUV that the brunette beauty drove.

But Judge Paul Oetken — who took only an hour to return his decision — said Dilek, 34, was out of luck.

She should have known that lover Ronald Pecunies, a minority owner and COO of Mercedes-Benz of Greenwich, Conn., didn’t have the authority to ink her four-year pact without the permission of majority owner Arthur “Kitt” Watson Jr., Oetken said.

Pecunies, who remained married despite shacking up with Dilek in a Central Park South love nest, used a private lawyer to draw up her contract, intentionally executed it without witnesses and never told Watson about it, the judge noted.

Oetken admitted that it was “a hard case” to decide, in part because of the no-questions-asked “gentlemen’s agreement” that Watson acknowledged he and Pecunies had regarding the employment of their respective wives and girlfriends.